You're correct, as far as we know, the hypothesis of panpsychism is unfalsifiable. The idea that this makes it unviable is called Logical Positivism. Personall

You're correct, as far as we know, the hypothesis of panpsychism is unfalsifiable. The idea that this makes it unviable is called Logical Positivism. Personally, I think Logical Positivism is short-sighted and uncomfortable with ambiguity. But that's more of an aesthetic preference than a scientific assertion.